1. Field of the Invention
The present invention relates to a method for processing a wafer to facilitate the handling of the wafer formed thin.
2. Related Art
A wafer in which a plurality of devices such as ICs or LSIs are formed on its front surface side, is split into the individual devices by employing a dicing apparatus or the like. The devices are assembled in various electronic equipment, and are extensively used. Besides, in order to attain a smaller size, a lighter weight, etc. for the electronic equipment, the wafer before being split into the individual devices is formed to a thickness of, for example, 100 m –50 m by grinding the back surface thereof.
In this regard, when the wafer is thinned by the grinding, its rigidity is lost, so that the wafer becomes difficult to handle in later steps. By way of example, it becomes difficult to cover the back surface of the wafer with a metal film made of gold, silver, titanium or the like, for the purpose of a probe test, and electrical testing of the devices become difficult. Therefore, a technique wherein the back surface of the wafer is ground in a state where a supporter is bonded to the front surface has been proposed with the intention of facilitating the handling (refer to, for example, JP-A-2004-22634 and JP-A-2003-209083).
However, when the supporter is bonded to the front surface of the wafer, it needs to be torn off later. This poses the problem that, even after the supporter has been torn off, an adhesive agent sometimes remains on the devices formed in the front surface. A troublesome operation is required for completely removing the adhesive agent, and the handling of the wafer becomes difficult in this respect.